Embedded magnet rotor and rotating electric machine

Abstract

To provide an embedded magnet type rotor capable of suppressing induced voltage while maintaining strength against centrifugal force at high speed rotation.SOLUTION: An embedded magnet type rotor has a plurality of magnetic poles formed in the circumferential direction of an iron core. Each of the magnetic poles of the iron core has a magnet hole to accommodate a main magnet. A gap part extending along the main magnet is formed between a first face of the main magnet facing the inner circumferential side of the rotor and the magnet hole. A second face of the main magnet facing the outer circumferential side of the rotor is in surface contact with the magnet hole.SELECTED DRAWING: Figure 2

Description

[Technical Field] 【0001】 This invention relates to an embedded magnet type rotor and a rotating electric machine. [Background technology] 【0002】 Conventionally, rotating electric machines have been used that include a stator around which a coil is wound, and a rotor that is mounted inside the stator and rotatable around a rotation axis relative to the stator. As an embedded magnet type rotor applicable to this type of rotating electric machine, a configuration is known in which a first magnet extending in the circumferential direction and a pair of second magnets inclined to spread radially outward are arranged at one magnetic pole (see, for example, Patent Document 1). 【0003】 Furthermore, Patent Document 2 proposes providing a gap between the outer and inner walls of the magnet insertion hole in the iron core to reduce the no-load induced voltage and thereby increase the torque of the rotating electric machine. [Prior art documents] [Patent Documents] 【0004】 [Patent Document 1] Japanese Patent Publication No. 2017-147810 [Patent Document 2] International Publication No. 2019 / 087747 [Overview of the Initiative] [Problems that the invention aims to solve] 【0005】 For example, high power density is required for rotating electric machines used in main motors for automobiles. Methods for increasing the power density of rotating electric machines include increasing the rotational speed of the machine to reduce the torque required to obtain the same output, and reducing the size of the iron core. 【0006】 In designing rotating electric machines suitable for high-speed rotation as described above, ensuring sufficient centrifugal force resistance of the rotor is crucial because the peripheral speed of the rotor increases. Furthermore, embedded magnet rotors have permanent magnets that provide a fixed magnetic flux, and therefore generate induced voltage as they rotate. Since the induced voltage increases proportionally with the rotor speed, it is also necessary to suppress the induced voltage below the inverter's voltage rating. 【0007】 In the design of rotating electric machines, especially those suitable for high-speed rotation, the ability to tolerate higher rotational speeds directly translates to miniaturization. Therefore, it is crucial to suppress induced voltage while ensuring strength against centrifugal force. 【0008】 On the other hand, in the case of the above-mentioned Patent Document 2, a gap is provided on the outer wall surface of the magnet insertion hole, so the contact surface between the iron core and the magnet becomes extremely narrow. As a result, when rotational centrifugal force is applied to the rotor, stress concentrates on the narrow contact surface with the magnet on the outer wall side of the magnet insertion hole, making it difficult to handle high-speed rotation in reality. 【0009】 The present invention has been made in view of the above circumstances, and provides an embedded magnet type rotor that can suppress induced voltage while ensuring strength against centrifugal force during high-speed rotation. [Means for solving the problem] 【0010】 One aspect of the present invention is an embedded magnet rotor having multiple magnetic poles formed in the circumferential direction of an iron core, wherein each magnetic pole of the iron core has a magnet hole formed therein that penetrates the iron core along the axis of rotation and houses a main magnet, and the magnet hole has a placement region in which the main magnet is placed and a gap portion communicating with this placement region, and the gap portion is between the first surface of the main magnet placed in the placement region facing the inner circumference side of the rotor and the magnet hole, along the main magnet in a plane perpendicular to the axis of rotation across the ends of the main magnet It is elongated and formed in a predetermined trapezoidal shape. , functions as a flux barrier The arrangement has an inner circumferential gap, and the second surface of the main magnet placed in the arrangement area, facing the outer circumference of the rotor, is in surface contact with the magnet hole, while the first surface is in surface contact with the wall surface of the arrangement area of ​​the magnet hole on both sides of the inner circumferential gap. 【0011】 In the above-described embedded magnet type rotor, the main magnet and the magnet hole may be arranged at the magnetic pole center. Further, the first surface of the main magnet and the air gap portion may extend in a direction orthogonal to the magnetic pole center. In the above-described embedded magnet type rotor, the main magnet and the magnet hole may be arranged to face each other in a tapered shape with the magnetic pole center therebetween. Further, the first surface of the main magnet and the air gap portion may extend while being inclined with respect to the direction orthogonal to the magnetic pole center. A rotating electric machine according to another aspect of the present invention includes a stator and the above-described embedded magnet type rotor. 【Advantages of the Invention】 【0012】 According to one aspect of the present invention, it is possible to provide an embedded magnet type rotor capable of suppressing an induced voltage while ensuring strength against centrifugal force during high-speed rotation. 【Brief Description of the Drawings】 【0013】 [Figure 1] It is a cross-sectional view of the rotating electric machine of the present embodiment. [Figure 2] It is a diagram showing a rotor and a stator for one magnetic pole in the present embodiment. [Figure 3] It is a diagram showing the iron core of the rotor in FIG. 2. [Figure 4] It is a schematic view showing the width and height of the air gap portion facing the inner peripheral side long side of the first magnet. [Figure 5] (a) is a graph showing the change in the armature interlinkage magnetic flux with respect to the height of the air gap portion. (b) is a graph showing the change in the inductance difference between the d-axis and the q-axis with respect to the height of the air gap portion. [Figure 6] (a) is a graph showing the change in the armature interlinkage magnetic flux with respect to the width of the air gap portion. (b) is a graph showing the change in the inductance difference between the d-axis and the q-axis with respect to the width of the air gap portion. [Figure 7] It is a graph showing the change rates of the induced voltage, the magnet torque, the reluctance torque, and the torque with respect to the height of the air gap portion. [Figure 8] It is a graph showing the change rates of the induced voltage, the magnet torque, the reluctance torque, and the torque with respect to the width of the air gap portion. [Figure 9] (a) is a diagram showing the stress distribution of the rotor in the embodiment. (b) is a diagram showing the stress distribution of the rotor in the comparative example. [Figure 10] This graph shows the fundamental wave component of the gap magnetic flux density under no-load conditions in the examples and comparative examples. [Figure 11] This figure shows the average torque of the examples and comparative examples when the maximum torque current is applied. [Figure 12] This graph shows the change in the demagnetization rate of the magnets in the examples and comparative examples. [Figure 13] This figure shows a rotor and stator for one magnetic pole in a first modified example of this embodiment. [Figure 14] This is a diagram showing the iron core of the rotor in Figure 13. [Figure 15] This figure shows a rotor and stator for one magnetic pole in a second modified example of this embodiment. [Figure 16] This is a diagram showing the iron core of the rotor in Figure 15. [Figure 17] This figure shows a rotor and stator for one magnetic pole in a third modified example of this embodiment. [Figure 18] This is a diagram showing the iron core of the rotor in Figure 17. [Figure 19] This figure shows a rotor and stator for one magnetic pole in a fourth modified example of this embodiment. [Figure 20] This is a diagram showing the iron core of the rotor in Figure 19. [Modes for carrying out the invention] 【0014】 Embodiments of the present invention will be described below with reference to the drawings. In the embodiments, for the sake of clarity, structures and elements other than the main parts of the present invention will be simplified or omitted in the description. Also, the same elements will be denoted by the same reference numerals in the drawings. Note that the shapes and dimensions of each element shown in the drawings are schematic representations and do not represent the actual shapes and dimensions. 【0015】 Figure 1 is a cross-sectional view showing a cross-section of the rotating electric machine of this embodiment in a direction perpendicular to the rotation axis Ax. 【0016】 The rotating electric machine 1 shown in Figure 1 is an inner rotor type motor, specifically an embedded magnet type synchronous motor (IPMSM) that requires high power density, such as a motor for a vehicle. The rotating electric machine 1 has a rotor 2, which is an example of an embedded magnet type rotor, and a cylindrical stator 3 arranged on the outer circumference of the rotor 2. In Figure 1, the extension direction of the rotation axis Ax of the rotating electric machine 1 is perpendicular to the plane of the paper. 【0017】 A stator 3 is positioned on the outer circumference of the rotor 2, separated by an air gap. In the rotating electric machine 1, the magnetic field of the stator 3 is sequentially switched by controlling the current of the coil 3b, causing the rotor 2 to rotate around the rotation axis Ax due to the attractive or repulsive force with the magnetic field of the rotor 2. 【0018】 The stator 3 houses the rotor 2 in a central space centered on the rotation axis Ax. Multiple teeth 3a are arranged on the inner circumference of the stator 3 at equal intervals in the circumferential direction, each protruding radially inward toward the rotation axis Ax. Slots are formed between adjacent teeth 3a. Coils 3b are mounted in the slots of the stator 3 along the outer circumference of the rotor 2. 【0019】 The rotor 2 has an iron core 4, a shaft 5, and permanent magnets, a first magnet 6 and a second magnet 7. The iron core 4 of the rotor 2 is, for example, a cylindrical member formed by stacking punched silicon steel sheets in the axial direction. An insulating adhesive is interposed between the individual silicon steel sheets that make up the iron core 4, so that the individual silicon steel sheets are insulated from each other. A shaft 5 is fitted into the axial center of the iron core 4 along the rotation axis Ax. In the rotating electric machine 1, the shaft 5 is rotatably supported by a bearing (not shown). 【0020】 The rotor 2 in this embodiment is an 8-pole rotor, and the iron core 4 of the rotor 2 has first magnets 6 and second magnets 7 arranged in a predetermined configuration such that eight magnetic poles are formed at equal intervals along the circumferential direction. The first magnets 6 and second magnets 7 are arranged such that adjacent magnetic poles in the circumferential direction have opposite polarities. The cross-sectional shapes of the first magnets 6 and second magnets 7 intersecting in the axial direction are both rectangular. 【0021】 Figure 2 shows the rotor 2 and stator 3 for one magnetic pole in this embodiment. Figure 3 shows the iron core 4 of the rotor 2 in Figure 2. 【0022】 Here, in the case of one magnetic pole of the iron core 4, the axis connecting the axis of rotation (rotation axis Ax) of the rotor 2 in Figure 1 and the magnetic pole center that generates magnetic torque becomes the d-axis of the dq-axis coordinate system. Also, the axis perpendicular to the above d-axis in terms of electrical angle becomes the q-axis of the dq-axis coordinate system. The portion of the rotor 2 between a pair of adjacent q-axes becomes the auxiliary magnetic pole section that generates reactance torque. 【0023】 A first magnet hole 11 is formed on the outer diameter side of the d-axis of the iron core 4. In addition, a pair of second magnet holes 12 are formed in the iron core 4 on the inner diameter side of the first magnet hole 11. The first magnet hole 11 and the second magnet holes 12 are each formed to penetrate the iron core 4 along the extension direction (axial direction) of the rotation axis Ax. 【0024】 A first magnet 6, which serves as the main magnet, is fitted into the first magnet hole 11, and a second magnet 7 is fitted into the second magnet hole 12. The first magnet 6 and the second magnet 7 are magnetized in a direction perpendicular to the long side of the magnet in a plane perpendicular to the rotation axis Ax. Furthermore, the magnetic pole surfaces of the first magnet 6 and the second magnet 7 facing the outer circumference are both aligned to have the same magnetic polarity (south pole or north pole) in the same magnetic pole. 【0025】 The first magnet hole 11 is formed near the outer circumference of the iron core 4 and extends in a direction perpendicular to the d-axis in a plane perpendicular to the rotation axis Ax. The first magnet hole 11 has a placement region 11a for the first magnet 6 and gaps 11b and 11c that communicate with the placement region 11a. Gap of the first magnet hole 11 (Inner circumferential gap) Portion 11b faces the inner surface (first surface) 6a of the first magnet 6, and the gap portions 11c face both ends of the long side of the first magnet 6. The gap portion 11b has a trapezoidal shape, with a narrower width on the inner side than on the outer side. These gap portions 11b and 11c function as flux barriers that smooth the flow of magnetic flux, improving torque and reducing magnet losses. 【0026】 As a result, the first magnet 6, which is fitted into the first magnet hole 11, is positioned to extend in a direction perpendicular to the d-axis, and the gap 11b is also formed to extend along the first magnet 6 in a direction perpendicular to the d-axis. On the other hand, no gap is formed on the outer circumference side of the first magnet 6, and the outer surface (second surface) 6b of the first magnet 6 is in surface contact with the first magnet hole 11 except for both ends. 【0027】 The pair of second magnet holes 12 are opposite each other across the d-axis and are formed in the iron core 4 in a tapered pattern, with the distance between them increasing as they approach the outer circumference of the iron core 4. The second magnet holes 12 have the arrangement region 12a of the second magnet 7 at their center, and gaps 12b that form flux barriers face both ends of the long side of the second magnet 7. 【0028】 The function of the gap 11b facing the first magnet 6 in this embodiment will be described in detail below. 【0029】 (Flux linkage and induced voltage) Figure 4 is a schematic diagram showing the width w and height h of the gap 11b facing the first magnet 6. In the gap 11b, the length w of the portion along the inner surface 6a of the first magnet 6 is referred to as the width of the gap 11b, and the length (height) h perpendicular to the width of the gap 11b is referred to as the height of the gap 11b. In the example shown in Figure 4, the dimensions of the main magnet, the first magnet 6, are set to a height of 3 mm and a width of 12 mm. 【0030】 Fig. 5(a) is a graph showing the change of the armature interlinkage flux ψ with respect to the height of the air gap portion 11b. a Fig. 5(b) is a graph showing the change of the inductance difference |L d -L q | between the d-axis and the q-axis with respect to the height of the air gap portion 11b. The horizontal axis in Figs. 5(a) and (b) represents the height h of the air gap portion 11b in Fig. 4. The vertical axis in Fig. 5(a) represents the armature interlinkage flux ψ a , and the vertical axis in Fig. 5(b) represents the inductance difference |L d -L q |. 【0031】 Also, Fig. 6(a) is a graph showing the change of the armature interlinkage flux ψ a with respect to the width of the air gap portion 11b. Fig. 6(b) is a graph showing the change of the inductance difference |L d -L q | between the d-axis and the q-axis with respect to the width of the air gap portion 11b. The horizontal axis in Figs. 6(a) and (b) represents the width w of the air gap portion 11b in Fig. 4. The vertical axis in Fig. 6(a) represents the armature interlinkage flux ψ a , and the vertical axis in Fig. 6(b) represents the inductance difference |L d -L q |. 【0032】 From Figs. 5(a) and Fig. 6(a), as the dimension of the air gap portion 11b facing the main magnet increases, the armature interlinkage flux ψ a tends to decrease. Also, from Figs. 5(b) and Fig. 6(b), as the dimension of the air gap portion 11b facing the main magnet increases, the inductance difference |L d -L q | tends to expand. 【0033】 Here, since the induced voltage V 0uv is the product of the angular velocity ω and the armature interlinkage flux ψ machine according to the following formula (1), the magnitude of the induced voltage V a is proportional to the magnitude of the armature interlinkage flux ψ 0uv . The magnitude of the induced voltage V machine is proportional to the magnitude of the armature interlinkage flux ψ a . 【0034】 【Equation】 【0035】 In this embodiment, as described above, the magnetic flux linkage is reduced by the air gap 11b facing the first magnet 6, so the induced voltage can be reduced. 【0036】 (Magnetic torque and reluctance torque) Next, the torque characteristics of the rotor 2 with the above-mentioned gap 11b will be described. Generally, the torque T generated in the IPMSM is expressed by the following equation (2). The first term of equation (2) represents the magnet torque due to the magnetic flux of the magnet, and the second term of equation (2) represents the reluctance torque due to the inductance difference. 【0037】 【number】 【0038】 The magnetic torque is given by the number of pole pairs P, as shown in equation (2). n , electric machine Sub-linked magnetic flux ψ a and the q-axis component of the line current (i q ) is the product of the electric current, therefore the magnitude of the magnet torque is the product of the electric current. machine Sub-linked magnetic flux ψ a It is proportional to this. In this embodiment, as described above, the magnetic flux linkage decreases due to the air gap 11b facing the first magnet 6, so the magnet torque also decreases. 【0039】 On the other hand, in this embodiment, the air gap 11b reduces the inductance of the d axis and increases the inductance of the q axis, resulting in an inductance difference (L) between the d axis and the q axis. d -L q The reluctance torque increases. Therefore, in the configuration of this embodiment, the reluctance torque increases, and the decrease in magnet torque can be compensated for by the reluctance torque. Accordingly, according to the configuration of this embodiment, it is possible to maintain a torque that is almost the same as that of a configuration without the above-mentioned gap 11b (comparative example described later). 【0040】 Figure 7 is a graph showing the rate of change of induced voltage, magnet torque Tmag, reluctance torque Tre, and torque T with respect to the height h of the air gap 11b. Figure 8 is a graph showing the rate of change of induced voltage, magnet torque Tmag, reluctance torque Tre, and torque T with respect to the width w of the air gap 11b. The horizontal axis of Figure 7 represents the height h of the air gap 11b in Figure 4, and the horizontal axis of Figure 8 represents the width w of the air gap 11b in Figure 4. The vertical axes of Figures 7 and 8 show the reduction rate of induced voltage (left vertical axis in the figure) and the increase rate of torque (right vertical axis in the figure) for torque. Note that in Figures 7 and 8, torque is calculated using predetermined current amplitude and current phase. 【0041】 Electrical factors that cause induced voltage machine Sub-linked magnetic flux ψ a To reduce this, it is necessary to consider the magnetic resistance due to the gap 11b. machine Sub-linked magnetic flux ψ a The magnetic flux is proportional to the gap flux, and the gap flux can be determined by subtracting the leakage flux of the bridge section and the gap flux due to the air gap 11b from the magnetic flux of the magnet. Furthermore, the gap flux due to the air gap 11b is inversely proportional to its magnetic resistance. Therefore, as the height of the air gap 11b increases, the gap flux increases, and the magnetic flux and electric flux increase. machine Sub-linked magnetic flux ψ a This reduces the force. The dimensions of the above-mentioned gap 11b are determined by parameters such as the magnetic force and dimensions of the permanent magnet used, the allowable torque value, or the required reduction rate of induced voltage. 【0042】 (Centrifugal force resistance) Figure 9 shows the stress distribution with respect to centrifugal force in the rotors of the examples and comparative examples. Figure 9(a) shows the stress distribution of the rotor in an embodiment corresponding to the configuration in Figure 2 of the above embodiment, and Figure 9(b) shows the stress distribution of the rotor in a comparative example. Both Figures 9(a) and (b) are for a rotational speed of 30,000 min⁻¹. -1The stress distribution at that time is shown. Furthermore, the comparative example in Figure 9(b) corresponds to the configuration in which the air gap 11b facing the inner surface 6a of the first magnet 6 is removed from the embodiment in Figure 9(a) (the air gap 11b is filled with the iron core 4). 【0043】 Also, rotation speed 30,000 min⁻¹ -1 Table 1 shows the von Mises stress values ​​for the example and comparative example. In Table 1, the center rib is the region enclosed by the dashed line in Figures 9(a) and (b) (the region sandwiched between the inner diameter ends of the second magnet hole 12). The maximum von Mises stress is the maximum stress generated in the outer diameter portion of the rotor. 【0044】 [Table 1] 【0045】 Comparing the example and the comparative example, the stress distribution hardly changes depending on the presence or absence of the above-mentioned void 11b, and no localized stress concentration occurs in the configuration of the example. Therefore, it can be said that the centrifugal force resistance of the configuration of the example is almost equivalent to that of the centrifugal force resistance of the configuration of the comparative example. 【0046】 (No load characteristics) Figure 10 is a graph showing the fundamental wave component of the gap magnetic flux density under no-load conditions in the examples and comparative examples. The horizontal axis of Figure 10 represents the electrical angle, and the vertical axis represents the amplitude of the fundamental wave of the gap magnetic flux density. In Figure 10, the maximum value of the fundamental wave component of the comparative example is set to 1, and the fundamental wave component of the examples is shown normalized. Furthermore, the calculation results of the no-load characteristics in the examples and comparative examples are shown in Table 2. 【0047】 [Table 2] 【0048】 In the configuration of this embodiment, the above-mentioned gap 11b allows electricity machine The sub-linked magnetic flux decreases. As a result, as shown in Figure 10, the gap magnetic flux density is reduced in this embodiment compared to the comparative example, and the following effects can be obtained. 【0049】 Firstly, in the embodiment, the induced voltage is reduced in proportion to the reduction in gap magnetic flux density. Secondly, in the embodiment, the amplitude of torque pulsation is reduced by the reduction in gap magnetic flux density, thereby reducing cogging torque. Thirdly, in the embodiment, the stator iron loss under no load is also reduced by the reduction in gap magnetic flux density. 【0050】 (Maximum Torque Characteristics) Figure 11 shows the average torque of the example and comparative example when the current that yields the maximum torque (maximum torque current) is applied to the coil. The horizontal axis of Figure 11 represents the current phase, and the vertical axis represents the average torque. Table 3 shows the calculation results of the average torque and torque ripple when the maximum torque current is applied to the coil in the example and comparative example. 【0051】 [Table 3] 【0052】 Referring to the average torque when the current phase is 0 [deg] in the example and comparative example, in the example, the current is affected by the air gap 11b. machine It can be seen that the magnet torque decreases compared to the comparative example due to the decrease in sub-linked flux. Furthermore, referring to the average torque when the current phase of the example and comparative example is 50 degrees, it can be seen that the average torque of the example and comparative example are almost the same due to the increase in reluctance torque in the example. In addition, the torque ripple when the maximum torque current is applied to the coil is almost the same in the example and comparative example. Therefore, the influence of the configuration of the example is almost negligible in the rotation region of maximum torque. 【0053】 (Demagnetization resistance) Figure 12 is a graph showing the change in magnet demagnetization rate in the example and comparative example. In Figure 12, neodymium sintered magnets are housed in the first magnet hole of the rotor of the example and comparative example, and the results of analysis confirming the demagnetization due to the demagnetizing field at each magnet temperature (coercivity) are shown. The horizontal axis of Figure 12 represents the magnet temperature, and the vertical axis represents the demagnetization rate. The demagnetization rate refers to the rate of decrease relative to the fundamental wave component of the induced voltage before the application of the demagnetizing field. From Figure 12, the demagnetization rate of the example shows a trend that is almost the same as that of the comparative example. Therefore, it can be seen that the demagnetization resistance is not impaired by the air gap 11b. 【0054】 (summary) As described above, the iron core 4 of the rotor 2 in this embodiment has a first magnet hole 11 for housing the first magnet 6 as the main magnet, and a gap 11b extending along the first magnet 6 is formed between the first magnet hole 11 and the inner circumferential surface 6a of the first magnet 6. In this embodiment, the formation of the above-mentioned gap 11b suppresses the induced voltage of the rotor 2, thereby reducing the induced voltage, while also reducing cogging torque and no-load iron loss. Even when the above-mentioned gap 11b is formed on the inner circumferential side of the first magnet 6, the torque characteristics, centrifugal force resistance, and demagnetization resistance of the rotor 2 are not impaired. 【0055】 Furthermore, in this embodiment, the outer surface 6b of the first magnet 6 is in surface contact with the first magnet hole 11, so the contact area between the first magnet 6 and the iron core 4 can be sufficiently widened on the outer surface of the rotor 2 where centrifugal force acts. The larger the contact area between the outer surface 6b of the first magnet 6 and the iron core 4, the larger the area that receives the load due to centrifugal force, and therefore the smaller the stress generated in the rotor 2. For this reason, in this embodiment, it is easy to ensure the strength of the rotor 2 against centrifugal force at high rotational speeds. 【0056】 Furthermore, as a secondary effect of forming the above-mentioned gap 11b in the rotor 2 to reduce the induced voltage, the reduced induced voltage provides a margin in the voltage withstand capability of the inverter elements, thus allowing the rotating electric machine 1 to rotate at even higher speeds. 【0057】 <Modified examples of embodiments> Modifications of this embodiment will be described below. In the description of each modification, components similar to those in the above embodiment will be denoted by the same reference numerals, and redundant explanations will be omitted. 【0058】 Figure 13 shows the rotor 2 and stator 3 for one magnetic pole in the first modified example of this embodiment. Figure 14 shows the iron core 4 of the rotor 2 in Figure 13. 【0059】 The first modified example is one in which only the first magnet 6 is placed on the rotor 2, and corresponds to a configuration in which the second magnet hole 12 and the second magnet 7 are removed from the rotor 2 in Figure 2. In the first modified example as well, a gap 11b is formed on the inner circumference side of the first magnet 6 by the first magnet hole 11, and the outer surface 6b of the first magnet 6 is in surface contact with the iron core 4, so the same effects as in the above embodiment are achieved. 【0060】 Figure 15 shows the rotor 2 and stator 3 for one magnetic pole in a second modified example of this embodiment. Figure 16 shows the iron core 4 of the rotor 2 in Figure 15. The second modified example is a configuration in which a pair of first magnets 6 are arranged in a tapered shape. 【0061】 In the second modification, a pair of first magnet holes 11 are formed in the iron core 4 of the rotor 2 so as to be symmetrical with respect to the magnetic pole center. The pair of first magnet holes 11 face each other across the d-axis and are arranged in a tapered pattern, with the spacing between them increasing as they approach the outer circumference of the iron core 4. The first magnet hole 11 has an arrangement region 11a for the first magnet 6 and gaps 11b and 11c that communicate with the arrangement region 11a. The gap 11b faces the inner surface 6a of the first magnet 6, and the gaps 11c face both ends of the long side of the first magnet 6, respectively. In the second modification, the inner surface 6a of the first magnet 6 and the gaps 11b extend at an inclination with respect to the d-axis and its perpendicular direction. 【0062】 In the second modified example, a gap 11b is formed on the inner circumference side of the first magnet 6 by the first magnet hole 11, and the outer surface 6b of the first magnet 6 is in surface contact with the iron core 4, thus achieving the same effects as in the above embodiment. 【0063】 Figure 17 shows a rotor 2 and stator 3 for one magnetic pole in a third modified example of this embodiment. Figure 18 shows the iron core 4 of the rotor 2 in Figure 17. The third modified example is a configuration in which the first magnet 6 and the second magnet 7 are each arranged in a tapered shape in pairs. 【0064】 In the third modified example, a pair of first magnet holes 11 and a pair of second magnet holes 12 are formed in the iron core 4 of the rotor 2 so as to be symmetrical with respect to the magnetic pole center. The first magnet holes 11 and the second magnet holes 12 are opposite each other across the d-axis and are arranged in a tapered pattern, with the distance between them increasing as they approach the outer circumference of the iron core 4. 【0065】 The first magnet hole 11 of the third modified example has a placement area 11a for the first magnet 6 and gaps 11b and 11c that communicate with the placement area. The gap 11b faces the inner circumferential surface 6a of the first magnet 6, and the gaps 11c face both ends of the long side of the first magnet 6. 【0066】 In the third modified example, the second magnet hole 12 is formed on the inner diameter side of the first magnet hole 11. Each second magnet hole 12 has a central area 12a for the placement of the second magnet 7, and gaps 12b that form flux barriers face both ends of the long side of the second magnet 7. In the third modified example, the inner circumferential surface 6a of the first magnet 6 and the gap 11b extend inclined with respect to the d axis and its perpendicular direction. 【0067】 In the third modified example, a gap 11b is formed on the inner circumference side of the first magnet 6 by the first magnet hole 11, and the outer surface 6b of the first magnet 6 is in surface contact with the iron core 4, thus achieving the same effects as in the above embodiment. 【0068】 Figure 19 shows the rotor 2 and stator 3 for one magnetic pole in a fourth modified example of this embodiment. Figure 20 shows the iron core 4 of the rotor 2 in Figure 19. The fourth modified example is a configuration in which a first magnet 6 and radially extending spoke magnets 8 are arranged at one magnetic pole. 【0069】 In the fourth modified example, the iron core 4 of the rotor 2 has a first block 4a on the outer circumference and a second block 4b on the inner circumference, with a gap formed between the first block 4a and the second block 4b. The first block 4a and the second block 4b are connected by a radially extending bridge 4c. 【0070】 In the first block 4a, a pair of first magnet holes 11 are formed so as to be symmetrical with respect to the magnetic pole center. The first magnet holes 11 are opposite each other across the d-axis and are arranged in a tapered pattern, with the spacing between them increasing as they approach the outer circumference of the first block 4a. The first magnet holes 11 have a placement area 11a for the first magnet 6 and gaps 11b and 11c that communicate with the placement area 11a. The gap 11b faces the inner circumferential surface 6a of the first magnet 6, and the gaps 11c face both ends of the long side of the first magnet 6, respectively. In the fourth modified example, the inner circumferential surface 6a of the first magnet 6 and the gaps 11b extend inclined with respect to the d-axis and its perpendicular direction. 【0071】 Furthermore, a radially extending groove 4d is formed on the q-axis of the first block 4a. Radially extending spoke magnets 8 are fitted into each groove 4d. The spoke magnets 8 are permanent magnets and are magnetized in the direction perpendicular to the short side of the magnet (radial direction) in a plane perpendicular to the rotation axis Ax. 【0072】 In the fourth modified example, a gap 11b is formed on the inner circumference side of the first magnet 6 by the first magnet hole 11, and the outer surface 6b of the first magnet 6 is in surface contact with the iron core 4, thus achieving the same effects as in the above embodiment. In Figure 19, an example is shown in which a pair of main magnets are arranged in a tapered shape in the first block 4a, but in the fourth modified example, one main magnet may be arranged in the first block 4a so as to extend in a direction perpendicular to the d-axis. 【0073】 The present invention is not limited to the embodiments described above, and various improvements and design modifications may be made without departing from the spirit of the invention. 【0074】 Although the above embodiment describes an example configuration with an 8-pole rotor, the number of poles of rotor 2 is not limited to the above embodiment. Furthermore, although the above embodiment describes an example configuration for a motor, the embedded magnet rotor of the present invention may also be applied as a rotor for a generator. Moreover, when the embedded magnet rotor of the present invention is applied to a motor, the application of the motor is not limited to electric vehicles. 【0075】 Furthermore, although the above embodiments and modifications show examples where each void in the rotor 2 is empty space, these voids may be filled with a non-magnetic, low-permeability metal (for example, aluminum or brass), adhesive, varnish, resin, etc. 【0076】 Furthermore, the embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of symbols] 【0077】 1...Rotating electric machine, 2...Rotor, 3...Stator, 4...Core, 5...Shaft, 6...First magnet, 6...Inner surface, 6b...Outer surface, 7...Second magnet, 8...Spoke magnet, 11...First magnet hole, 11a...Placement area, 11b,11c...Gap, 12...Second magnet hole

Claims

[Claim 1] An embedded magnet type rotor having multiple magnetic poles formed in the circumferential direction of the iron core, Each of the aforementioned magnetic poles of the iron core has a magnetic hole formed therein that penetrates the iron core along the axis of rotation and houses the main magnet. The magnet hole has a placement region in which the main magnet is placed and a gap that communicates with this placement region. The aforementioned void portion has an inner circumferential void portion that functions as a flux barrier, extending along the main magnet in a plane perpendicular to the rotation axis and spanning between both ends of the main magnet, between the first surface facing the inner circumference side of the rotor of the main magnet arranged in the arrangement region and the magnet hole, and is formed in a predetermined trapezoidal shape. The second surface of the main magnet positioned in the aforementioned arrangement area, facing the outer circumference of the rotor, is in surface contact with the magnet hole, and the first surface is in surface contact with the wall surface of the arrangement area of ​​the magnet hole on both sides of the inner circumferential gap. Embedded magnetic rotor. [Claim 2] The main magnet and the magnet hole are positioned at the center of the magnetic pole. The first surface and the gap of the main magnet extend in a direction perpendicular to the magnetic pole center. The embedded magnet type rotor according to claim 1. [Claim 3] The main magnet and the magnet hole are arranged opposite each other in a tapered shape, separated by the magnetic pole center. The first surface and the gap of the main magnet extend inclined with respect to the direction perpendicular to the magnetic pole center. The embedded magnet type rotor according to claim 1. [Claim 4] Stator and, The embedded magnet rotor according to any one of claims 1 to 3 and A rotating electric machine equipped with the following features.

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